U. Poppe, Y.Y. Divin, M.I. Faley, C.L. Jia and P.M.Shadrin

The surface morphology, microstructure and transport properties of epitaxial YBa2Cu307 thin films deposited on vicinal substrates of SrTiO3 by high pressure oxygen sputtering were studied. Furthermore the electrical and structural properties of YBa2Cu307 Josephson junctions on vicinal offcut SrTiO3 bicrystals with different grain boundary types were investigated in detail. This included junctions with a 2x 12° tilt or twist of the YBa2Cu307 c-axis across the grain boundary. In comparison to conventional [OO1]-tilt grain boundaries bicrystal Josephson junctions showed high Ic Rn -products of up to 1.2 meV at 77 K and up to 8 meV at 4.2 K. IV-curve instabilities, probably of magnetic origin due to flux flow in the electrodes, often could be observed for junctions biased with high current densities.